Korean J Med.  2010 Apr;78(4):477-484.

Decreased expression of Na,K-ATPase in the kidneys of rats with two-kidney, one-clip hypertension

• Ma SK
• Oh YW
• Kim IJ
• Bae EH
• Lee JU
• Kim SW

Abstract

BACKGROUND/AIMS
This study investigated the role of Na,K-ATPase, the local renin-angiotensin-aldosterone system (RAAS), and atrial natriuretic peptide (ANP) system in the pathogenesis of renal tubular dysfunction and hypertension in rats with two-kidney, one-clip (2K1C) hypertension.
METHODS
Adult male Sprague-Dawley rats were made 2K1C hypertensive for 4 weeks. The renal expression of Na,K-ATPase was determined by immunoblotting. The mRNA expression of renin, angiotensin-converting enzyme (ACE), aldosterone synthase (CYP11B2), mineralocorticoid receptor (MR), and the ANP system were determined in the kidney using real-time polymerase chain reaction.
RESULTS
The blood pressure was increased in the 2K1C rats, compared with controls. The plasma renin activity and serum aldosterone concentrations were increased, as were the urine output and fractional excretion of sodium. The expression of Na,K-ATPase protein was decreased in the clipped kidney, as compared with the control kidney, while it remained unchanged in the contralateral kidney. The mRNA expression of renin, ACE1, CYP11B2, and MR was increased in the clipped kidney, but unchanged in the non-clipped kidney. The mRNA expression of ACE2 did not differ between the groups. The expression of ANP mRNA was increased in both clipped and non-clipped kidneys, as compared with control kidneys.
CONCLUSIONS
The enhanced activity of the local RAAS may result in to ischemic tubular injury and the development of hypertension in 2K1C rats. The downregulation of Na,K-ATPase associated with tubular injury in the clipped kidney may account for the impaired tubular sodium reabsorption in 2K1C hypertension.

Keyword

Renovascular hypertension; Na,K-ATPase; Aldosterone synthase; Atrial natriuretic peptide

MeSH Terms

Adult
Aldosterone
Aldosterone Synthase
Animals
Atrial Natriuretic Factor
Blood Pressure
Down-Regulation
Humans
Hypertension
Hypertension, Renovascular
Immunoblotting
Kidney
Male
Plasma
Rats
Rats, Sprague-Dawley
Receptors, Mineralocorticoid
Renin
Renin-Angiotensin System
RNA, Messenger
Sodium
Aldosterone
Aldosterone Synthase
Atrial Natriuretic Factor
RNA, Messenger
Receptors, Mineralocorticoid
Renin
Sodium